The proposed research will compare the effectiveness of two treatment models for adults with co-occurring substance abuse and serious mental illness (dually diagnosed): 12-Step based versus Rational Recovery on SMART based psychosocial rehabilitation programs. No definitive research has been done to evaluate the effectiveness of either of these two approaches with the dually diagnosed. The goal of the proposed research is to provide objective criteria for selection of treatment specifically suited to the dually diagnosed individual. The specific aims of the proposed research are to determine (1) the differential efficacy of these two treatment approaches with this challenging population; and (2) whether the specific subject characteristics given below will contribute to the differential efficacy of the two approaches. It is hypothesized that subjects with external locus of control, strong religious beliefs, and a tendency to view substance abuse as a disease will do better in 12-Step treatment. It is hypothesized that subjects with internal locus of control, weak religious beliefs, and a tendency to view substance abuse as a bad habit will do better in Rational Recovery based treatment. Also investigated will be whether subjects in later stages of recovery will show a more positive treatment outcome than subjects in earlier stages of recovery with both treatments or if this will interact with treatment modality. Funding has been requested for 5 years. Eight cohorts of 10 subjects will be examined in each study group, for a total of 80 subjects in each of the two study groups. Each cohort will participate in residential treatment for 6 months. A multiple group, multiple baseline, comparison group design is proposed. The subjects will be adults of mixed ethnicity and gender, with a large proportion of Mexican-American subjects, reflecting the ethnic and gender balance of the referral population. Subjects will be assigned from the agency's waiting list using matching criteria for gender, ethnicity, broad diagnostic category, and orientation toward substance abuse. The proposed research will take place at the Dual Diagnosis Program of La Frontera Center, Inc., in Tucson, Arizona. La Frontera has one of the longest running community-based programs designed to treat the dually diagnosed. Treatments and assessments will be multidimensional. Initial assessments will include diagnoses, psychosocial history, medical history, mental status, reading skills, orientation toward substance abuse, substance abuse-related locus of control, strength of spiritual beliefs, stage of addiction recovery, and recent life functioning in ten areas (e.g., affect/mood, legal, family/social, cognitive, self-care). Outcome measures include levels of functioning, quality of life, and substance use during treatment and during follow-up. Satisfaction with treatment, treatment compliance, disruptive behavior, and stage of addiction recovery will also be measured. Process measures will also be made. Quantitative data will be analyzed with the general linear model procedure. A power analysis indicated that the subject number is large enough to detect meaningful changes in the factors to be studied. This study will benefit clients, clinicians, and researchers alike, as the knowledge base for matching dually diagnosed individuals with treatments will be expanded.